You have to figure out object tree to find the path from one object to another.
Then you step up the hierarchy by _parent pointer and down the hierarchy by object names in the tree path.
In case some object in the tree does not have a name (possible in SWF) you have to assign it a name in order to make it accessible by AS2 script.
Note that it is the name of object instance where placed, not object class name in a library as one defined object may have multiple copies populated in the tree.
I have no idea how your tool works, I do everything in rudimentary FFDec where I have to figure out object tree in my head manually by tracing PlaceObject() name parameters.